ELECTROPHORETIC DISPLAY WITH THERMAL CONTROL

• US 20080218471A1
• Filed: 06/22/2007
• Published: 09/11/2008
• Est. Priority Date: 10/07/2003
• Status: Active Grant

• Current Assignee: E Ink Corporation (E Ink Holdings Incorporated)
• Original Assignee: SiPix Imaging, Inc. (E Ink Holdings Incorporated)
• Inventors: Sprague, Robert A., Liang, Rong-Chang, Chung, Jerry
• Granted Patent: US 8,514,168 B2
• Time in Patent Office: Days
• US Class Current: 345/107
• CPC Class Codes: G02F 1/133382 Heating or cooling of liquid crystal cells other than for activation, e.g. circuits or arrangements for temperature control, stabilisation or uniform distribution over the cell
• CPC Class Codes: G02F 1/133385 with cooling means, e.g. fans
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G02F 1/1675 Constructional details

Abstract

An electrophoretic display (EPD) with thermal control is disclosed for controlling and maintaining an image in extreme temperature environments. Techniques are also disclosed for maintaining the EPD cell threshold voltage for EPD cells comprising an EPD display media at or above a desired level in an environment in which the EPD may be subjected to an extreme temperature. The techniques comprise sensing a sensed temperature associated with the EPD display media, determining whether the sensed temperature satisfies a criterion established to ensure that the display media temperature remains at a level associated with an acceptable EPD cell threshold voltage, and in the event it is determined that the sensed temperature does not satisfy the criterion, controlling the EPD display media temperature as required to bring the sensed temperature to a level that satisfies the criterion.

Claims

1. An EPD module structure, comprising:

i) an EPD panel comprising EPD cells filled with EPD display media; and

ii) a thermal control pad which is capable of controlling the temperature associated with the EPD display media to ensure that the threshold voltage of the EPD cells is equal to or greater than one third of a driving voltage used to drive the EPD cells to a desired display state.

2. The EPD module structure of claim 1, further comprising a clear front plate.

3. The EPD module structure of claim 1, further comprising a metal plate.

4. The EPD module structure of claim 1 further comprising an air gap.

5. The EPD module structure of claim 1 further comprising a thermal barrier sheet.

6. The EPD module structure of claim 1 further comprising an electric power source.

7. The EPD module structure of claim 6 wherein said electric power source is a solar cell panel.

8. The EPD module structure of claim 1 wherein said thermal control pad comprises a heating element.

9. The EPD module structure of claim 8 wherein said heating element is a radiant heater.

10. The EPD module structure of claim 8 wherein said heating element is a convection heater.

11. The EPD module structure of claim 8 wherein said heating element is a resistive heater.

12. The EPD module structure of claim 1 wherein said thermal control pad comprises a cooling element.

13. The EPD module structure of claim 12 wherein the cooling element is a refrigerant or coolant.

14. The EPD module structure of claim 13 wherein said refrigerant or coolant is in the form of a gas.

15. The EPD module structure of claim 13 wherein said refrigerant or coolant is in the form of a liquid.